1. Field of the Invention
This invention relates to a display apparatus having a liquid crystal display panel, and more particularly to a liquid crystal display apparatus wherein a backlight apparatus in the form of a fluorescent lamp is disposed on the back face side of a liquid crystal panel so that the liquid crystal panel is illuminated by the backlight apparatus.
2. Description of the Prior Art
A display apparatus which makes use of a liquid crystal display panel is advantageous in that a television receiver can be constructed with a reduced thickness comparing with another television receiver which makes use of a CRT (cathode ray tube). Due to the advantage, television receivers making use of a liquid crystal display panel have been put into practical use. When a television receiver of the type including a liquid crystal display panel is constructed as a television receiver of the reflecting type, there is a drawback that it is so low in brightness that an image thereon cannot be observed clearly. Therefore, a display apparatus has been proposed wherein a backlight apparatus in the form of a fluorescent lamp is disposed on the rear face side of a liquid crystal panel and backlight from the backlight apparatus is distributed uniformly by a diffusing plate so that it may illuminate the liquid crystal display panel uniformly.
A display apparatus of the type wherein a fluorescent lamp is employed as a backlight apparatus, however, has a drawback that, as time passes, drops of mercury are deposited on the inner surface of the tube thereof and make the brightness thereof non-uniform. In particular, there is a drawback that mercury enclosed in the fluorescent lamp is condensed and deposited and locally stricks to the inner surface of the tube of the fluorescent lamp and decreases the brightness at the portions of the tube at which the mercury sticks. While the brightness of the tube is made more uniform to some degree by the diffusing plate, if the amount of mercury sticking to the tube increases, then the illumination upon the liquid crystal display panel becomes non-uniform.